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The sternum (from Greek st?????, sternon, "chest" or breastbone) is a long flat bone
Bone

Bones are rigid organ that form part of the endoskeleton of vertebrates. They function to move, support, and protect the various organs of the body, produce red blood cell and white blood cells and store minerals....
 located in the center of the thorax
Chest

The chest is a part of the anatomy of humans and various other animals sometimes referred to as the thorax....
 (chest). It connects to the rib bones
Rib

In vertebrate anatomy, ribs are the long curved bones which form the ribcage. In most vertebrates, ribs surround the chest and protect the lungs, heart, and other internal Organ s of the thorax....
 via cartilage
Cartilage

Cartilage is a type of dense connective tissue. It is composed of specialized cells called chondrocyte that produce a large amount of extracellular matrix composed of collagen fibers, abundant ground substance rich in proteoglycan, and elastin fibers....
, forming the rib cage with them, and thus helps to protect the lungs, heart
Heart

The heart is a muscle organ in all vertebrates responsible for pumping blood through the blood vessels by repeated, rhythmic contractions, or a similar structure in annelids, mollusks, and arthropods....
 and major blood vessels from physical trauma
Physical trauma

Physical trauma refers to a body injury. A trauma patient is someone who has suffered serious and life-threatening physical injury with the potential for secondary complications such as Shock , respiratory failure and death....
.

The sternum is sometimes cut open (a median sternotomy
Median sternotomy

Median sternotomy is a type of surgical procedure in which a vertical inline incision is made along the sternum, after which the sternum itself is divided, or "cracked"....
) to gain access to the thoracic contents when performing cardiothoracic surgery.

sternum is an elongated, flattened bone, forming the middle portion of the anterior wall of the thorax.






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The sternum (from Greek st?????, sternon, "chest" or breastbone) is a long flat bone
Bone

Bones are rigid organ that form part of the endoskeleton of vertebrates. They function to move, support, and protect the various organs of the body, produce red blood cell and white blood cells and store minerals....
 located in the center of the thorax
Chest

The chest is a part of the anatomy of humans and various other animals sometimes referred to as the thorax....
 (chest). It connects to the rib bones
Rib

In vertebrate anatomy, ribs are the long curved bones which form the ribcage. In most vertebrates, ribs surround the chest and protect the lungs, heart, and other internal Organ s of the thorax....
 via cartilage
Cartilage

Cartilage is a type of dense connective tissue. It is composed of specialized cells called chondrocyte that produce a large amount of extracellular matrix composed of collagen fibers, abundant ground substance rich in proteoglycan, and elastin fibers....
, forming the rib cage with them, and thus helps to protect the lungs, heart
Heart

The heart is a muscle organ in all vertebrates responsible for pumping blood through the blood vessels by repeated, rhythmic contractions, or a similar structure in annelids, mollusks, and arthropods....
 and major blood vessels from physical trauma
Physical trauma

Physical trauma refers to a body injury. A trauma patient is someone who has suffered serious and life-threatening physical injury with the potential for secondary complications such as Shock , respiratory failure and death....
.

The sternum is sometimes cut open (a median sternotomy
Median sternotomy

Median sternotomy is a type of surgical procedure in which a vertical inline incision is made along the sternum, after which the sternum itself is divided, or "cracked"....
) to gain access to the thoracic contents when performing cardiothoracic surgery.

Overview

The sternum is an elongated, flattened bone, forming the middle portion of the anterior wall of the thorax. Its upper end supports the clavicles (Collar bones), and its margins articulate with the cartilages of the first seven pairs of ribs. Its top is also connected to the Sternocleidomastoid muscle
Sternocleidomastoid muscle

In human anatomy, the sternocleidomastoid muscle, also known as sternomastoid and commonly abbreviated as SCM, is a paired muscle in the superficial layers of the anterior portion of the neck....
. It consists of three parts, from above downward:

  • Manubrium
    Manubrium

    The manubrium or manubrium sterni is the broad, upper part of the sternum. With a quadrangular shape, wider superiorly and narrower inferiorly, it articulates with the clavicles and the first two ribs....
  • Body of sternum
    Body of sternum

    The body of the sternum , considerably lengthier, narrower, and thinner than the manubrium, attains its greatest breadth close to the lower end....
     (gladiolus)
  • Xiphoid process
    Xiphoid process

    The xiphoid Process , also known as the xiphisternum is a small Cartilage extension to the lower part of the sternum which is usually Ossification in the adult human....


In its natural position, the inclination of the bone is oblique from above, downward and forward. It is slightly convex in front and concave behind; broad above, becoming narrowed at the point where the manubrium joins the body, after which it again widens a little to below the middle of the body, and then narrows to its lower extremity. Its average length in the adult is about 17 cm
Centimetre

A centimetre is a Units of measurement of length in the metric system, equal to one hundredth of a metre, which is the current International System of Units SI base unit of length....
, and is rather longer in the male than in the female.

In early life its body is divided in three segments, called sternebrœ (singular: sternebra).

Structure

The sternum is composed of highly vascular cancellous tissue, covered by a thin layer of compact bone which is thickest in the manubrium between the articular facets for the clavicles.

Articulations

The sternum articulates on either side with the clavicle and upper seven costal cartilages
Costal cartilages

The costal cartilages are bars of hyaline cartilage which serve to prolong the ribs forward and contribute very materially to the elasticity of the walls of the thorax....
.

Fractures of the sternum

Fractures of the sternum
Sternal fracture

A sternal fracture is a bone fracture of the sternum , located in the center of the chest. The injury, which occurs in 5?8% of people who experience significant blunt chest trauma, may occur in vehicle accidents, when the still-moving chest strikes a steering wheel or dashboard or is injured by a seatbelt....
 are rather uncommon. However, they may result from trauma, such as when a driver's chest is forced into the steering column
Steering column

The automotive steering column is a device intended primarily for connecting the steering wheel to the steering mechanism by transferring the driver's input torque from the steering wheel....
 of a car in a car accident
Car accident

A car accident is a road traffic incident that usually involves one road vehicle collision with another vehicle or other road user, animal, or a stationary roadside object, and may result in injury, property damage, and possibly death....
. A fracture of the sternum is usually a comminuted
Comminuted

Comminuted may refer to:*Bone fracture, as in a crushed or splintered bone*comminuted material, which has been pulverised or titurated, such as Pulverised fuel ash in coal burning...
 fracture, meaning it is broken into pieces. The most common site of sternal fractures is at the sternal angle
Sternal angle

The sternal angle or 'angle of Louis' is the angle formed by the junction of the manubrium and the body of the sternum in the form of a secondary cartilaginous joint ....
. However, some studies reveal that repeated punches or continual beatings, sometimes called "sternum punches", to the sternum area have also caused fractured sternums. Sternum fractures are frequently associated with underlying injuries such as pulmonary contusion
Pulmonary contusion

A pulmonary contusion is a contusion of the lung, caused by chest trauma. As a result of damage to capillary, blood and other fluids accumulate in the lung tissue....
s, or bruised lung tissue.

Additional images


See also

  • Ossification of sternum
    Ossification of sternum

    The sternum originally consists of two cartilaginous bars, situated one on either side of the median plane and connected with the cartilages of the upper nine ribs of its own side....
  • Bone terminology
    Bone

    Bones are rigid organ that form part of the endoskeleton of vertebrates. They function to move, support, and protect the various organs of the body, produce red blood cell and white blood cells and store minerals....
  • Terms for anatomical location
  • Pectus carinatum
    Pectus carinatum

    Pectus carinatum, also called pigeon chest, is a deformity of the chest characterized by a protrusion of the sternum and ribs....
  • Pectus excavatum
    Pectus excavatum

    Pectus excavatum is the most common congenital deformity of the anterior wall of the chest, in which several ribs and the sternum grow abnormally....